Concurrent manufacture of sodium cyanate and fatty alcohols



Patented Aug. 7, 1951 CONCURRENT MANUFACTURE OF SODIUM I CYANATE AND FATTY ALCOHOLS Jonas Kamlet, New York, N. Y., assignor to Emery Industries, Inc., Cincinnati, Ohio, a corporation of Ohio No Drawing. Application April 1, 1950, Serial No. 153,480

9 Claims.

This invention relates to a method of utilizing metallic sodium for the concurrent manufacture of sodium cyanate (or sodium cyanide, whichever is the more valuable commercially) and fatty alcohols without consumption of metallic sodium over and above that requisite for the production of either product alone by usual methods. At the present time, sodium cyanide is manufactured by reacting metallic sodium, ammonia and carbon at a relatively elevated temperature. As a separate operation, some of this cyanide is converted into sodium cyanate suitable for some specialized industrial uses, but traces of the highly poisonous cyanide are apt to be present, which disqualifies the product for many purposes, and further, the total cost of the product precludes its utilization for many purposes for which it is chemically suited. Fatty alcohols are at present produced in large commercial quantities by reduction of fatty acid esters and triglycerides with metallic sodium, with attendant degradation of the sodium to caustic soda. The present process may be regarded alternatively as a method of producing fatty alcohols without consumption of metallic sodium additional to that normally required for the manufacture of sodium compounds of the cyanate-cyanide type or as a method of manufacturing these sodium salts without using any more sodium than that required for the conven tional fatty alcohol process.

Regarded from either point of view, this invention is predicated on the discovery and determination that the reacting power, propensity and utility of a given quota of metallic sodium may be twice employed in a single process to do the work and produce the products which now require double the consumption of metallic sodium.

The present process produces first, a very pure sodium cyanate, which is devoid of even traces of the poisonous sodium cyanide, but which may be reduced, if desired, to the cyanide if the economic value of the latter is deemed greater than that of the sodium cyanate. While the cyanate, at present, is higher priced than the cyanide, this process produces sodium cyanate at a cost inherently below that of sodium cyanide. Actually, the value of the fatty alcohols which are concurrently produced permits further processing cf the sodium cyanate to sodium cyanide without a total cost which renders the cyanide so produced uncompetitive with cyanide now on the market. In short, the process of the present invention produces two valuable commercial commodities virtually at the price of either, regard- 2 less of the apportionment matter of bookkeeping.

Apart from the advantage of the present process in the production of the specified sodium compounds, the process constitutes specific improvements in the method of producing fatty alcohols, in that the present sodium process of producing fatty alcohols inherently creates large quantities of caustic glycerine water which are of very limited industrial utility and value. The separation of caustic and glycerine water is very difficult. In fact the only significant use for this solution is in the manufacture of soaps which of their values as a are essentially competitive with the chief outlet.

for fatty alcohols, the detergent industry.

That is, these caustic glycerine water byproducts can be used only to manufacture fatty acid soaps by the soap kettle method which results in the production of four molecules of fatty acid soap for each molecule of fatty alcohol produced. Since fatty alcohols are usually sulfated for detergent use and so modified compete with fatty acid soaps, the normal production of fatty alcohols by sodium reduction is economically inflexible. The method of this invention avoids the production of a competitive by-product and in fact results in end products of approximately equal stature.

Thus, viewed from the point of production of fatty alcohols or sodium cyanate or cyanide, the process of the present invention provides conspicuous advantages, the most dramatic of which is that a single atom of sodium is sequentially utilized to do the work which requires two atoms of sodium according to the methods precedent to this invention. Since metallic sodium is an expensive product which is particularly difficult to store, ship and handle without deterioration, the economic benefits of the present invention are substantial.

In its broadest terms, this invention comprises reacting metallic sodium with esters in the presence of reducing alcohol to produce sodium alcoholates, then reacting the sodium alcoholates with urea to produce alcohols and sodium cy-' anate. If desired, the sodium cyanate may be reduced to sodium cyanide without elevating the cost of the cyanide to uneconomic proportions if the market value of the fatty alcohols be properly reflected in the accounting.

The fatty esters employed in this process may be any of the animal and vegetable fats, oils and waxes which are produced by nature. Synthetic esters of the same type of structural formula may be used such as methyl oleate, ethyl stearate,

3 butyl iaurate, etc. Such esters may be described as the reaction products of the higher aliphatic carboxylic acids with monohydric or polyhydric alcohols.

In general, it is believed to be desirable to use commercial fats and oils as the source of the fatty esters, but ester type waxes may also be used. Such fats and oils, however, must be very low in free fatty acid content to avoid wastage of expensive metallic sodium by the production of sodium soaps. If it is desired to use a cheaper grade of fat or oil, which is characterized by substantial free fatty acid content, then the fat or oil may be esterified, for instance with a monohydric alcohol, to produce a synthetic ester. Also, since techniques for segregating various discrete individual fatty acids are well-known, whereas corresponding techniques for segregating the corresponding alcohols have not yet been developed, an individual fatty acid may be esteritied and used in this process if it is desirable to produce the corresponding individual fatty alcohol.

The process involves initially reacting the ester with metallic sodium in the presence of reducing alcohol. This need be no difierent from the first step of the conventional process of manufacturing fatty alcohols by sodium reduction, but from the point of view of succeeding operations, it is desirable that the reducing alcohol be chosen in relation to its boiling point to provide a relatively high boiling point for the mixture resulting from the sodium reaction. That is, even though the reactivity of the reducing alcohol is an important factor, some activity may be sacrificed with a. view to promoting theurea reaction. This consideration also applies to the selection of the neutral diluent which is usually employed for protecting the sodium from the atmosphere during its introduction into the reaction and/or for thinning the viscosity of the reaction mixture. Preferably, the alcohols are high boiling secondary alcohols such as sec-butyl alcohol, methyl butyl carbinol (methyl amyl alcohol), cyclohexanol (hexalin), etc., or such tertiary alcohols as tertbutyl and tert-amyl, and while the diluent may be the conventional toluene, I prefer to use the higher boiling point xylene. As in Example 7, the sodium reduction is often carried out in an atmosphere of nitrogen.

In the first step of the process, utilizing natural fats as the ester, one molecule of the fatty tri-glyceride and six molecules of reducing alcohol are reacted with twelve atoms of sodium to produce three molecules of a sodium alcoholate of fatty alcohol, one molecule'of tri-sodium glycerate and six molecules of a sodium alcoholate of the reducing alcohol. As indicated, a thinner or diluent of neutral type which does not enter into the reaction is usually employed and if desired an excess of reducing alcohol may be added to further thin the mixture after the reaction is completed. Or, as indicated in Example 2, the inert diluent may be removed after the reduction is completed.

As a second step the reaction mixture is heated with urea at a temperature of from 110 to 200 0., preferably above the melting point of urea, which is 133 C. I have found that the reaction initiates and proceeds even if no excess of alcohol is present to bring the urea into solution; that is, the urea may be reacted directly with the alcoholates resulting from a stoichiometrical mixture of the original reactants. I have further found that, if any unreacted particles of sodium should remain in the reaction vessel, the addition of urea results in the elimination of such particles and in the avoidance of dangers involved in the handling of solutions containing metallic sodium. This urea reaction produces sodium cyanate, which precipitates from the mixture; alcohols, including fatty alcohols and glycerine; and ammonia gas, which is drawn from the reaction chamber. Preferably this reaction is conducted under reflux conditions to prevent loss of alcohol and diluent. I have found that the speed of the urea, sodium alcoholate reaction is a function of temperature. Thus, the use of higher boiling reducing alcohols and xylene, e. g., permits this reflux to be conducted at efilcient temperatures. If necessary, pressure may be employed to raise the boiling points.

By the term alcoholates as used in the preceding paragraph and throughout this disclosure, I intend to comprehend the reaction products of metallic sodium with each of the chains of the original ester molecules, 1. e., sodium salts of the lower aliphatic alcohols such as methyl, ethyl, isopropyl and butyl, the sodium compounds formed in such reactions which have organic chain lengths corresponding to those of the higher fatty acids, and the compounds of sodium and polyhydric alcohols such as glycol and glycerine, depending upon the identity of the ester employed. Even though no solution of urea is constituted, still the alcoholates react with urea, and the sodium cyanate thus formed in the reaction is precipitated, so that the reaction goes substantially to completion.

The sodium cyanate is separated from the alcohols after the completion of the reaction by filtration, centrifuging or the like, accompanied by washing of the precipitate with alcohol or other liquid which is solvent for the alcohols of the reaction mixture but not for the sodium cyanate.

The next step of the process is the separation of the cyanate-free alcohols. If the fatty ester originally treated with the metallic sodium in the presence of the reducing alcohol is a synthetic ester of a fatty acid with a lower molecular weight alcohol then the corresponding alcohol may be topped off with the reducing alcohol by distillation, after which the fatty alcohols are themselves distilled, if desired, to improve their purity. If, on the other hand, natural fats or oils, that is, tri-glycerides are used as the starting material, as is recommended in view of their availability and lower price, the glycerine must be separated from the other alcohols, that is, the fatty alcohols and reducing alcohol. This is done by washing the alcoholic mixture with water. Naturally, the stronger the glycerine water, the less further refining it requires. While as much water as desired or convenient may be employed to wash out the glycerine, it is possible to eilect a good separation by the use of an amount of water for washing purposes which does not substantially exceed twice the weight of the glycerine contained in the mixture. Thus, a glycerine water is obtained which is of much higher strength than the glycerine water normally recovered from soap making.

Sodium cyanate is a versatile reagent in inorganic and organic chemistry. It may be used in the synthesis of cyanuric acid, alkyl ureas, aryl ureas, semicarbazide, N,N-hydrazodicarbonamide, ammeline, guanylurea, substituted pyrazolines, substituted isoxazoles, substituted imidazoles, etc. It has widespread application in agriculture as a selective weed killer and as a defoliant e. g., for cotton. It is used in saltbaths for. the treatment of aluminum and magnesium alloys, in case-hardening of steel and may find use in the extraction of gold and silver from their ores. In view of the substantial value of fatty alcohols and glycerine, however, the sodium cyanate, if desired, may be reduced to sodium cyanide, which at present enjoys a broader market than the sodium cyanate, without bringing the total cost of the sodium cyanide so produced to a figure above the cost of the production of sodium cyanide from metallic sodium by the conventional methods now in use. The reduction of sodium cyanate to sodium cyanide may be accomplished as follows;

NaCNO+CO- NaCN+COz Example 1 666 parts by weight of beef tallow and 346 parts by weight of secondary butyl alcohol were dissolved in 600 parts by weight of xylene and added to a stirred suspension of 217 parts by weight of sodium in 860 parts by weight of xylene at 105-110 C. After the reduction was complete, 570 parts by weight of urea was added to the reaction mixture which was then boiled under gentle reflux for four hours with continual agitation. Ammonia was evolved during the reaction. At the conclusion of the reflux period the reaction mixture was cooled to 50-60 C., and the precipitated sodium cyanate was filteredofl. The filtrate was then separated into its component constituents of fatty alcohols, sec-butyl alcohol, xylene and glycerine by washing the glycerine out with three 200 parts by weight portions of water and then fractionating the water in- 450' parts by weight of cottonseed oil and 244 parts by weight of tertiary butyl alcohol were dissolved in 1300 parts by weight of toluene and slowly added to a stirred suspension of 152 parts by weight of finely divided sodium and another 1300 parts by weight of toluene at 100-110 C. After the reduction was complete, the toluene was distilled oil from the reaction mixture and was replaced with 2350 parts by weight of tertiary butyl alcohol. 400 parts by weight of urea was added. Then the reaction mixture was boiled under gentle reflux for three hours until the ammonia evolution ceased, the mixture was cooled somewhat, the precipitate of sodium cyanate was filtered oil and the components of the filtrate were separated as described in Example 1. The yield of fatty alcohols was 322.5 parts by weight, equivalent to 85.2% of theoretical; the yield-of sodium cyanate (assaying 96.2% NaCNO) was 395 parts by weight, equivalent to 88.2% of theoretical.

Example 3 666 parts by weight of beef tallow and 477 parts by weight of methyl isobutyl carbinol were dissolved in 600 parts by weightof xylene and added slowly to a stirred suspension of 217 parts by weight of sodium and 860 parts by weight of xylene at 105-110 C. After the reduction was complete 570 parts by weight of urea was added to the reaction mixture which was then boiled to gentle reflux for three hours with continual agitation. At the conclusion of the reflux period the reaction mixture was cooled to 50-60 C., and the separated sodium cyanate was filtered oil; the filtrate was then separated into its components as described in Example 1.

The yield of fatty alcohol was 552 parts by weight representing a yield of 92.0% of theoretical; the yie of sodium cyanate (assaying 96.0% NaCNO) was 590 parts by weight, equivalent to 92.2% theoretical.

Example 4 100 parts by weight of methyl oleate together with 73.5 parts by weight of methyl isobutyl carbinol was dissolved in 315 parts by weight of xylene and slowly added to a suspension of 33.1 parts by weight of finely divided molten sodium and another 33.1 parts by weight of xylene maintained at 125-130 C. After all the ester mixture had been added, the reaction was continued for an additional one-half hour when all sodium particles had all substantially disappeared. Urea (86.3 parts by weight) was slowly added at this point, and the reaction continued at gentle reflux for three to four hours, ammonia being evolved with the formation of sodium cyanate by the reaction of urea-with the alcoholates present. The mixture was allowed to cool to -100 C. and the precipitated sodium cyanate was filtered off, washed with methyl lsobutyl carbinol and dried. Solvent was removed from the filtrate by distillation and the crude oleyl alcohol remaining was vacuum distilled at 10-15 mm.

The yield of crude oleyl alcohol was 86.0 parts by weight, of theory, while the yield of pure distilled oleyl alcohol was 75.5 parts by weight, 83.4% of theory; the sodium cyanate assayed 92 pure, weight yield being 91.6 parts by weight, 98% of theory.

Example 5 Methyl behenate, 300 parts by weight, together with 178.7 parts by weight of methyl isobutyl carbinol were dissolved in 180 parts by weight of xylene and slowly added to 80.7 parts by weight molten and finely divided sodium in another 80.7

parts by weight xylene maintained at 125-l30 C.

The reaction was continued an additional onehalf hour after all the ester had been added, the sodium then being substantially all used up. Urea, 210.0 parts by weight, was then added slowly and refluxed from threeto four hours with the evolution of ammonia and the formation of a precipitate of sodium cyanate. The mixture was cooled slightly to 100-110 C. and the sodium cyanate was filtered ofi, washed and dried. Solvent was removed from the filtrate by distillation and the crude fatty alcohol was dis tilled at 10-l5 mm. vacuum.

The yield of pure distilled behenyl alcohol was 85.0% of theory (235 parts by weight), the yield of sodium cyanate was 98.5% of theory (224.5 parts by weight) and its purity was 92.7%.

Example 6.

Coconut oil, 100 parts by weight, and methyl isobutyl carbinol, 98 parts by weight, were dis solved in 98 parts by weight of xylene and slowly added to a suspension of 44.1 parts by weight of cyanate.

, sodium'in 4451' parts by weight of xylene, the

temperature being held at approximately 130 C. An additional one-half hour reaction time then was used, after completion ofthe addition ofthe coconut oil. Urea (115.0 parts by weight) was added to the reaction flask and the mixture was refluxed for four hours, ammonia being evolved and sodium cyanate was filtered off, washed with methyl isobutyl carbinol and dried. The filtrate was added to hot watergiving a separation into an upper layer of solvents and fatty alcohol and a lower layer of water and glycerine. The solvents were removed from the upper layer by distillation and the crude fatty alcohol remaining was vacuum distilled at -15 mm. The glycerine water layer was concentrated by evaporation of the water.

The yield'of crude alcohol was 86.9 parts by weight or 98.8% of theory with a yield' of 74.3

parts by weight of pure distilled alcohol, 84.5% of theory; the yield of glycerine was 11.6 parts by weight or 88% of theory; the weight yield of sodium cyanate (116 parts by weight) was 94% of theory and its purity was 93.5%. g

Example 7 Refined and vacuum dried sperm oil esters, 100 parts by weight, together with42.8 parts'by weight dry methyl iscbutyl carbinol and 125.2 parts by weight of xylene were slowly added to a suspension of 19.3 parts by weight of finely divided molten sodium is approximately 100 parts by weight of xylene, the temperature being maintained at 125-27 C. during the addition. "Reaction was conducted in an atmosphere of nitrogen. After all the ester mix had been added, the reaction was continued for an additional onehalf hour at 125-2'7 C. and all the Na had substantially disappeared. Dry urea (50.3 parts by weight) was slowly added at this point, temperature dropping to 120-22 C. Reaction was con tinued at reflux for four and one-half hours, temperature rising gradually to 140 C., ammonia being evolved. and sodium cyanate formed. Mixture was then cooled to 110-20 C. and the insolublesodium cyanate filtered off, washed with methyl isobutyl carbinol, and dried. Solvent was removed from the filtrate by distillation and the crude alcohol remaining vacuum distilled at 10-15 mm. Yield of crude alcohol (97.8 parts by weight) was 97.3% of theory. Yield of distilled pure alcohol was 85.8 parts by weight or 85.3% of theory. Weight yield of sodium cyanate was 52 parts by weight or 95.7%, purity (after slight further washing) being 95%.

As analternative to the use of urea, thiourea may be employed following the sodium reduction with the resulting precipitate of sodium thio- From the foregoing description, it is to be observed that the employment of fats and oils in this process of manufacturing sodium cyanate from metallic sodium and urea yields detergentforming materials, fatty alcohols, which are superior to and more valuable than the corresponding fatty acid soaps and also such use yields glycerine water of much higher strength than that usually obtained as a by-product of soap making, both at a cost not substantially above that of the conventional methods of producing either sodium cyanateor fatty alcohols. By employing the appropriate ester, any specific fatty alcohol may be'prepared in conjunction with the manufacture of sodium cyanate.

Having described my invention, I claimi .1. A process'for; the treatment of the reaction mixture obtained by the sodium reduction of fats and oils in the presence of an aliphatic alcohol; said mixture containing the sodium salt of the aliphatic alcohol, the sodium salt of glycerine and the sodium salt of the fatty alcohol; which comprises reacting said mixture with urea whereby ammonia is evolved and sodium cyanate is formed, separating said formed sodium cyanate from the'resultant mixture containin aliphatic alcohol, glycerine and fatty alcohol, and fractionating the latter mixture to recover the aliphatic alcohol, the glycerine and the fatty alcohol.

2. The process for the manufacture of sodium cyanate which comprises treating the reaction mixture obtained by the sodium reduction of fats and oils in the presence of an aliphatic alcohol containing the sodium salt of the aliphatic alcohol, the sodium salt of glycerine and the sodium salt of the fatty alcohol, with urea, whereby ammonia is evolved and sodium cyanate is formed, and separating said formed sodium cyanate from the resultant mixture containing aliphatic alcohol, glycerine and fatty alcohol.

3. A method of utilizing sodium for the concurrent manufacture of sodium cyanate and fatty alcohol, said method comprising reacting metallic sodium with fatty ester in the presence of reducing alcohol to produce sodium alcoholates, reacting said resulting sodium alcoholatss with urea to produce alcohols and sodium cyanate, and separating'the alcohols from the sodium cyanate.

4. A method of utilizing sodium for the concurrent manufacture of, sodium cyanate and .fatty alcohol, said method comprising reacting metallic sodium with fatty tri-glycerides in the presence of reducing alcohol to produce sodium alcoholates, reacting said resulting sodium al- .coholates with urea to produce alcohols and sodium-cyanate and separating the alcohols from the sodium cyanate.

5. The method of producing sodium cyanate and fatty alcohol concurrently which comprises treating a mixture of reducing alcohol and fatty ester with metallic sodium to produce a mixture of sodium alcoholates, treating said mixture of sodium alcoholates with urea to produce sodium cyanate and alcohols, including the alcohol corresponding to the fatty component of the ester, .separating the sodium cyanate from the alcohols and separating thealcohols one from the others.

6. The method of producing sodium cyanate and fatty alcohol jointly from fatty tri-glycerides, urea and metallic sodium, said method comprising treating a mixture of fatty tri-glycerides and reducing alcohol with metallic sodium to produce a mixture of sodium alcoholates, reacting. said mixtureof sodium alcoholates with urea to produce sodium cyanate, glycerine and alcohols, including the alcohol corresponding to the fatty component of the tri-glyceride, separating the sodium cyanate from the alcoholsand glycerine and washing the mixture of alcohols and glycerine with water to remove the glycerine from the fatty alcohols.

7. The concurrent manufacture of sodium cy- .'anate and fatty alcohol, which comprises reacting metallic sodium with fatty ester in the presence of reducing alcohol to produce sodium alcoholates, reacting said mixture of sodium alcoholates with urea at a temperature of -200 C. to produce sodium cyanate and alcohols, in- .cluding the alcohol corresponding to the fatty component of the ester, separating the sodium cyanate from the alcohols, and separating the fatty alcohol from the remaining alcohols.

8. The method of concurrently producing sodiurn cyanate and fatty alcohol which comprises treating a mixture or reducing alcohol and fatty ester with metallic sodium to produce a mixture of sodium alcoholates, reacting said mixture of sodium alcoholates with urea at a temperature above that of the melting point of urea to produce sodium cyanate and alcohols, including the alcohol corresponding to the fatty component the ester, separating the sodium cyanate from the alcohols and effecting the separation of the alcohols into two or more fractions.

9. A method of utilizing sodium for the concurrent manufacture of sodium cyanate and fatty alcohols which comprises reacting metallic sodium dispersed in an inert hydrocarbon with fatty ester in the presence of a reducing second- 10 ary alcohol to produce sodium alcohoiates, react ing the mixture containing said sodium alcoholates with urea at the reflux temperature or the mixture to produce alcohols and sodium cy= anate and separating the alcohols irom the sodl= um cyanate.

JONAS KA.

REFERENCES CITED The following references are of record in the I file of this patent:

UNITED STATES PATENTS 

1. A PROCESS FOR THE TREATMENT OF THE REACTION MIXTURE OBTAINED BY THE SODIUM REDUCTIONS OF FATS AND OILS IN THE PRESENCE OF AN ALIPHATIC ALCOHOL; SAID MIXTURE CONTAINING THE SODIUM SALT OF THE ALIPHATIC ALCOHOL, THE SODIUM SALT OF GLYCERINE AND THE SODIUM SALT OF THE FATTY ALCOHOL; WHICH COMPRISES REACTING SAID MIXTURE WITH UREA WHEREBY AMMONIA IS EVOLVED AND SODIUM CYANATE IS FORMED, SEPARATING SAID FORMED SODIUM CYANATE FROM THE RESULTANT MIXTURE CONTAINING ALIPHATIC ALCOHOL, GLYCERINE AND FATTY ALCOHOL, AND FRACTIONATING THE LATTER MIXTURE TO RECOVER THE ALIPHATIC ALCOHOL, THE GLYCERINE AND THE FATTY ALCOHOL. 